Project Summary/Abstract Atrial fibrillation (AF) is the most common and clinically significant cardiac arrhythmia and results in impaired quality of life and substantially elevated risks for stroke, systemic thromboembolism and heart failure. Our preliminary data indicates that people living near HFOG well sites may experience increases in blood pressure and arterial stiffness that are associated with AF. The development of hydraulically fractured oil and natural gas (HFOG or ?fracking?) well sites is associated with two emerging environmental risk factors for AF, air and noise pollution. While this evidence indicates that AF patients who reside in close proximity to the development complications, is if the air and noise pollution that occur during the development of HFOG well sites contribute to the etiology and burden of AF. We lack the preliminary data necessary to justify and efficiently design the prospective study will be necessary to address the pressing need to understand these etiological relationships. Without this preliminary data, we are unable to advance methods to investigate the temporal relationships between environmental risks related to HFOG well sites and AF. Our long-term goal is to understand the epidemiological relationships between environmental risks associated with HFOG and AF related health outcomes. The overall objective for this proposal is to link the Colorado All Payer's Claim Database (APCD) and the Colorado O&G Information system (COGIS) to obtain the preliminary data necessary to justify and inform the design of a comprehensive cohort study. To meet this objective, we will employ a longitudinal interrupted time-series crossover design to retrospectively follow ~ 2500 AF patients in the APCD living within 1.6 kilometers (1-mile) of 830 HFOG well sites developed between 2010 and 2015. Our central hypothesis is that there is an increased risk of AF and AF associated morbidity during development of a HFOG well site to which women, the elderly, and those with pre-existing health conditions are more susceptible. We will determine and compare the incidence of claims with a principle diagnosis of AF and AF related mortality in AF patients living within 1.6 km of a HFOG well site before, during, and after development of the site. The proposed study will be the first to evaluate relationships between the development of HFOG well sites and AF related morbidity. Findings from our study will allow us to determine if a cohort study is warranted and if warranted, inform the design of such a study. This future study would prospectively follow populations for AF and related morbidity over the course of development of HFOG well sites while measuring specific environmental risk factors associated with this development. Considering the rapidly growing number of people living in close proximity to an HFOG well set, it is essential that we work to understand the associated health risks as soon as possible so that we can develop the best preventions and remedies for those people. of HFOG sites may be at a significantly greater risk for additional incidents of AF and associated it is not known